The present invention relates to a video processing technology of decoding a bit stream including encoded data of an image and generating a video signal for displaying the decoded image. In particular, the present invention relates to a multichannel video processing technology dealing with images of a plurality of channels.
In recent years, satellite digital broadcasting and terrestrial digital broadcasting have gained momentum in many countries of the world. In digital broadcasting, data such as images and voice is compressed and encoded in compliance with a scheme such as MPEG (moving picture experts group), and in many cases, images of a plurality of channels are distributed in the multiplexed state.
A digital broadcast receiver, which receives a bit stream including encoded data of images of a plurality of channels in the multiplexed state, basically separates a video stream and an audio stream of one designated channel from the bit stream, decodes the separated streams, and outputs the decoded streams.
In some cases, however, it becomes necessary to decode encoded data of, not only an image of a single channel, but also images of a plurality of channels and display the decoded images simultaneously. For example, Japanese Laid-Open Patent Publication No. 9-93131 discloses an apparatus including a plurality of decoders each adapted to decode a bit stream of one channel.
As described above, conventionally, a plurality of decoders are used for decoding encoded data of images of a plurality of channels. It is therefore difficult to reduce the cost for the decoders.